Nozzle for turbine system

ABSTRACT

A nozzle for a turbine system is disclosed. The nozzle includes an airfoil, an inner sidewall, and an outer sidewall. The airfoil includes exterior surface defining a pressure side and a suction side extending between a leading edge and a trailing edge. The airfoil further defines a tip and a root. The inner sidewall is connected to the airfoil at the tip. The outer sidewall is connected to the airfoil at the root. The inner sidewall and outer sidewall each includes a peripheral edge defining a pressure side slash face, a suction side slash face, a leading edge face, and a trailing edge face. At least one of the inner sidewall pressure side slash face, the inner sidewall suction side slash face, the outer sidewall pressure side slash face, or the outer sidewall suction side slash face has a generally curvilinear profile.

FIELD OF THE INVENTION

The present disclosure relates in general to turbine systems, such asgas turbine systems, and more particularly to nozzles in turbinesystems.

BACKGROUND OF THE INVENTION

Turbine systems are widely utilized in fields such as power generation.For example, a conventional gas turbine system includes a compressor, acombustor, and a turbine. During operation of the gas turbine system,various components in the system are subjected to high temperatureflows, which can cause the components to fail. Since higher temperatureflows generally result in increased performance, efficiency, and poweroutput of the gas turbine system, the components that are subjected tohigh temperature flows should be cooled to allow the gas turbine systemto operate at increased temperatures, increased efficiency, and/orreduced emissions.

As discussed, during operation of a turbine system, the variouscomponents thereof are subjected to high temperatures and otherwisesubjected to high stress environments. In many cases, this can lead tocracking of various components. One component that is of particularconcern is the nozzle. A typically turbine section nozzle includes anairfoil portion extending between inner and outer sidewall. Theperipheral edges, and in particular the pressure side and suction sideslash faces, of the sidewalls have linear profiles. For example, someedges have singular linear profiles that extend throughout the entireedge. Other profiles are “dogleg” profiles, which include two linearportions that meet to define an angle therebetween. In dogleg profilesin particular, the intersection between the linear portions creates ahigh stress concentration region. Relief radii have been introduced atthe intersections, but only slightly reduce the stress concentrationlevel. Singular linear profiles eliminated the high stressconcentrations at the intersection. However, the construction of a slashface with a singular linear profile requires that the slash face be inclose proximity to the leading edge and/or trailing edge of the airfoil,thus creating additional high stress concentration regions.

Accordingly, an improved nozzle for use in a turbine system is desiredin the art. In particular, a nozzle design that reduces or eliminatesstress concentrations in the sidewalls thereof would be advantageous.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one embodiment, a nozzle for a turbine system is disclosed. Thenozzle includes an airfoil, an inner sidewall, and an outer sidewall.The airfoil includes exterior surface defining a pressure side and asuction side extending between a leading edge and a trailing edge. Theairfoil further defines a tip and a root. The inner sidewall isconnected to the airfoil at the tip. The inner sidewall includes aperipheral edge defining a pressure side slash face, a suction sideslash face, a leading edge face, and a trailing edge face. The outersidewall is connected to the airfoil at the root. The outer sidewallincludes a peripheral edge defining a pressure side slash face, asuction side slash face, a leading edge face, and a trailing edge face.At least one of the inner sidewall pressure side slash face, the innersidewall suction side slash face, the outer sidewall pressure side slashface, or the outer sidewall suction side slash face has a generallycurvilinear profile.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a schematic view of a gas turbine system according to oneembodiment of the present disclosure;

FIG. 2 is a cross-sectional view of a turbine section of a gas turbinesystem according to one embodiment of the present disclosure;

FIG. 3 is perspective embodiment of a nozzle according to one embodimentof the present disclosure;

FIG. 4 is a profile view of a nozzle according to one embodiment of thepresent disclosure;

FIG. 5 is a schematic view of a curve utilized to define a curvilinearprofile of a nozzle peripheral edge according to one embodiment of thepresent disclosure; and

FIG. 6 is a schematic view of a curve utilized to define a curvilinearprofile of a nozzle peripheral edge according to another embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

FIG. 1 is a schematic diagram of a gas turbine system 10. It should beunderstood that the turbine system 10 of the present disclosure need notbe a gas turbine system 10, but rather may be any suitable turbinesystem 10, such as a steam turbine system or other suitable system. Thegas turbine system 10 may include a compressor section 12, a combustorsection 14, and a turbine section 16. The compressor section 12 andturbine section 16 may be coupled by a shaft 18. The shaft 18 may be asingle shaft or a plurality of shaft segments coupled together to formshaft 18.

As is generally known in the art, air or another suitable working fluidis flowed through and compressed in the compressor section 12. Thecompressed working fluid is then supplied to the combustor section 14,wherein it is combined with fuel and combusted, creating hot gases ofcombustion. After the hot gases of combustion are flowed through thecombustor section 14, they may be flowed into and through the turbinesection 18.

FIG. 2 illustrates one embodiment of portions of a turbine section 18according to the present disclosure. A hot gas path 20 may be definedwithin the turbine section 18. Various hot gas path components, such asshrouds 22, nozzles 24, and buckets 26, may be at least partiallydisposed in the hot gas path 20.

For example, as shown, the turbine section 18 may include a plurality ofbuckets 26 and a plurality of nozzles 24. Each of the plurality ofbuckets 26 and nozzles 24 may be at least partially disposed in the hotgas path 20. Further, the plurality of buckets 26 and the plurality ofnozzles 24 may be disposed in one or more annular arrays, each of whichmay define a portion of the hot gas path 20.

The turbine section 16 may include a plurality of turbine stages. Eachstage may include a plurality of buckets 26 disposed in an annular arrayand a plurality of nozzles 24 disposed in an annular array. For example,in one embodiment, the turbine section 16 may have three stages, asshown in FIG. 2. For example, a first stage of the turbine section 16may include a first stage nozzle assembly 31 and a first stage bucketassembly 32. The nozzles assembly 31 may include a plurality of nozzles24 disposed and fixed circumferentially about the shaft 18. The bucketassembly 32 may include a plurality of buckets 26 disposedcircumferentially about the shaft 18 and coupled to the shaft 18. Asecond stage of the turbine section 16 may include a second stage nozzleassembly 33 and a second stage buckets assembly 34. The nozzles 24included in the nozzle assembly 33 may be disposed and fixedcircumferentially about the shaft 18. The buckets 26 included in thebucket assembly 34 may be disposed circumferentially about the shaft 18and coupled to the shaft 18. The second stage nozzle assembly 33 is thuspositioned between the first stage bucket assembly 32 and second stagebucket assembly 34 along the hot gas path 20. A third stage of theturbine section 16 may include a third stage nozzle assembly 35 and athird stage bucket assembly 36. The nozzles 24 included in the nozzleassembly 35 may be disposed and fixed circumferentially about the shaft18. The buckets 26 included in the bucket assembly 36 may be disposedcircumferentially about the shaft 18 and coupled to the shaft 18. Thethird stage nozzle assembly 35 is thus positioned between the secondstage bucket assembly 34 and third stage bucket assembly 36 along thehot gas path 20.

It should be understood that the turbine section 16 is not limited tothree stages, but rather that any number of stages are within the scopeand spirit of the present disclosure.

It should be understood that hot gas path components according to thepresent disclosure are not limited to components in turbine sections 16.Rather, hot gas path components may be components at least partiallydisposed in flow paths for compressor sections 12 or any other suitablesections of a system 10.

FIGS. 3 and 4 illustrate embodiments of a nozzle 24 for a system 10. Inexemplary embodiments, the nozzle 24 is utilized in the turbine section18 of the system 10, and is thus included in a nozzle assembly. Further,the nozzle 24 is in exemplary embodiments a first stage nozzle 24, thusutilized in a first stage nozzle assembly 31. In other embodiments,however, the nozzle 24 could be a second stage nozzle 24 utilized in asecond stage nozzle assembly 33, a third stage nozzle 24 utilized in athird stage nozzle assembly 35, or any other suitable nozzle utilized inany suitable stage or other assembly, in a turbine section 18,compressor section 12, or otherwise.

As shown, a nozzle 24 according to the present disclosure includes oneor more airfoils 40, an inner sidewall 42, and an outer sidewall 44. Theairfoil 40 extends between the inner and outer sidewalls 42, 44 and isconnected thereto. The airfoil 40 includes exterior surfaces defining apressure side 52, a suction side 54, a leading edge 56, and a trailingedge 58. As is generally know, the pressure side 52 and the suction side54 each generally extend between the leading edge 56 and the trailingedge 58. The airfoil 40 further defines and extends between a tip 62 anda root 64. The inner sidewall 42 is connected to the airfoil 40 at thetip 62, while the outer sidewall 44 is connected at the root 64.

As discussed, the sidewalls 42, 44 are connected to the airfoil 40. Insome embodiments, the nozzle 24 is formed as a single, unitarycomponent, such as through casting, and the sidewalls 42, 44 and airfoil40 are thus connected. In other embodiments, the airfoil 40 andsidewalls 42, 44 are formed separately. In these embodiments, theairfoil 40 and sidewalls 42, 44 may be welded, mechanically fastened, orotherwise connected together.

As discussed, each nozzle 24 includes one or more airfoils 40. Eachairfoil 40 extends between and is connected to the sidewalls 42, 44.One, two (as shown), three, four or more airfoils 40 may thus beincluded in a nozzle 24. Further, as discussed, the nozzle 24 may beincluded in an annular array of nozzles 24 as a nozzle assembly.

The inner sidewall 42 includes a peripheral edge 70. The peripheral edge70 defines the periphery of the inner sidewall 42. In exemplaryembodiments, a peripheral edge 70 may thus include and define variousfaces which correspond to the various surfaces of the airfoil(s) 40. Forexample, as shown, a peripheral edge 70 may define a pressure side slashface 72, a suction side slash face 74, a leading edge face 76, and atrailing edge face 78.

Similarly, the outer sidewall 44 includes a peripheral edge 80. Theperipheral edge 80 defines the periphery of the outer sidewall 44. Inexemplary embodiments, a peripheral edge 80 may thus include and definevarious faces which correspond to the various surfaces of the airfoil(s)40. For example, as shown, a peripheral edge 80 may define a pressureside slash face 82, a suction side slash face 84, a leading edge face86, and a trailing edge face 88.

As discussed above, nozzle 24 peripheral edges with reduced oreliminated stress concentration regions are desired. As such, inexemplary embodiments, one or more of the inner sidewall 42 pressureside slash face 72, the inner sidewall 42 suction side slash face 74,the outer sidewall 44 pressure side slash face 82, or the outer sidewall44 suction side slash face 84 has a generally curvilinear profile.Having a curvilinear profile means that, in a profile view such as thatshown in FIG. 4, the subject slash face 72, 74, 82 and/or 84 is curvedthroughout generally the entire length thereof. A profile view, as shownin FIG. 4, is a top or bottom view of the nozzle 24.

The use of a curvilinear profile for a slashface 72, 74, 82, 84 isparticularly advantageous. For example, intersections between linearportions are eliminated, thus eliminating high stress concentrationregions that are caused by such intersections. Further, by curving theprofile, the subject slashface 72, 74, 82, 84 is spaced from the leadingedge 56 and/or trailing edge 58 of the nozzle airfoil 40 by an increaseddistance (discussed below) relative to a singular linear profile. Thisthus reduces the associated high stress concentration regions at theselocations. Additionally, curving of the profiles as described hereinprovides a variety of other advantages. For example, such curvingprovides a relatively more optimum aerodynamic shape to the innersidewall 42 and/or outer sidewall 44. Thus, the nozzles 24 in generalhave improved aerodynamics. Further, the relative positioning of thevarious adjacent slashfaces of adjacent nozzles is relatively moreoptimum, as discussed below.

As discussed, any one or more slash faces 72, 74, 82, 84 of a nozzle 24may have curvilinear profiles. In exemplary embodiments, all of theslash faces 72, 74, 82, 84 have curvilinear profiles. Further, inexemplary embodiments, each nozzle 24 in a nozzle assembly has matingslash face 72, 74, 82, 84 profiles, which may be curvilinear. Thus, forexample, the inner sidewall 42 pressure side slash face 72 may mate withthe inner sidewall 42 suction side slash face 74 of an adjacent nozzle24, the inner sidewall 42 suction side slash face 74 may mate with theinner sidewall 42 pressure side slash face 72 of an adjacent nozzle 24,the outer sidewall 44 pressure side slash face 82 may mate with theouter sidewall 44 suction side slash face 84 of an adjacent nozzle 24,and the outer sidewall 44 suction side slash face 84 may mate with theouter sidewall 44 pressure side slash face 82 of an adjacent nozzle 24.Such mating, and the use of seals (not shown) therebetween, mayfacilitate sealing of the nozzle assembly, thus preventing hot gas orcooling flow leakage therethrough.

FIGS. 5 and 6 illustrate schematic views of a curve 100 utilized todefine a curvilinear profile of a nozzle 24 peripheral edge 70, 80, suchas a slash face 72, 74, 82, 84 thereof, according to various embodimentsof the present disclosure. In some embodiments, as shown in FIG. 5 thecurve 100 is created using a single centerpoint 102 and a single radius104 extending from the centerpoint. The curvilinear profile of a slashface 72, 74, 82, 84 may thus be defined by this single centerpoint 102and a single radius 104. In other embodiments, the curve 100 is createdusing multiple centerpoints 102 and multiple radii 104 extendingtherefrom, with a radius 104 extending from each centerpoint 102. Thecurvilinear profile of a slash face 72, 74, 82, 84 may thus be definedby these multiple centerpoints 102 and a radii 104. For example, inexemplary embodiments, the curve is a spline, and the curvilinearprofile is thus a spline profile. Any suitable number of centerpoints102 and radii may be utilized according to the present disclosure, suchas one, two, three, four, five, ten, 20, 50, 100, etc. Further, in someembodiments, the curve and curvilinear profile may be designed using anysuitable software, such as a suitable computer aided design program. Inexemplary embodiments, a suitable computational fluid dynamics programmay be utilized.

In some embodiments, the curve 100 and curvilinear profile of one ormore slash faces 72, 74, 82, 84 may be further defined by a minimumdistance 112 between the slash face 72, 74, 76, 78 and the leading edge56 of the airfoil 40 and/or a minimum distance 114 between the slashface 72, 74, 76, 78 and the trailing edge 58 of the airfoil 40. Bymaintaining a suitable minimum distance 112 and/or 114, stressconcentrations at these locations may be reduced and or eliminated.Required minimum distances 112, 114 to reduce stress concentrationsbelow a required level may be determined for a particular nozzle 24based on the individual characteristics of that nozzle 24, and thecurves 100 and curvilinear profiles, and thus the sidewalls 42, 44, maybe designed such the distances 112 and/or 114 are equal to or greaterthan the required minimum distances. The required minimum distances maybe predetermined for a nozzle 24 or determined during design of thenozzle 24, such as through design iterations when designing the curves100 for the slash face 72, 74, 82, 84 curvilinear profiles. The curves100 and curvilinear profiles may thus be designed such that the minimumdistances 112, 114 are equal to or greater than the required minimumdistances.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A nozzle for a turbine system, the nozzlecomprising: an airfoil comprising exterior surface defining a pressureside and a suction side extending between a leading edge and a trailingedge, the airfoil further defining a tip and a root; an inner sidewallconnected to the airfoil at the tip, the inner sidewall comprising aperipheral edge defining a pressure side slash face, a suction sideslash face, a leading edge face, and a trailing edge face; and an outersidewall connected to the airfoil at the root, the outer sidewallcomprising a peripheral edge defining a pressure side slash face, asuction side slash face, a leading edge face, and a trailing edge face,wherein at least one of the inner sidewall pressure side slash face, theinner sidewall suction side slash face, the outer sidewall pressure sideslash face, or the outer sidewall suction side slash face has agenerally curvilinear profile.
 2. The nozzle of claim 1, wherein theinner sidewall pressure side slash face and the outer sidewall pressureside slash face each has a generally curvilinear profile.
 3. The nozzleof claim 1, wherein the inner sidewall suction side slash face and theouter sidewall suction side slash face each has a generally curvilinearprofile.
 4. The nozzle of claim 1, wherein the inner sidewall pressureside slash face, the outer sidewall pressure side slash face, the innersidewall suction side slash face and the outer sidewall suction sideslash face each has a generally curvilinear profile.
 5. The nozzle ofclaim 1, wherein the curvilinear profile is defined by a singlecenterpoint and a single radius extending from the centerpoint.
 6. Thenozzle of claim 1, wherein the curvilinear profile is defined by aplurality of centerpoints and a plurality of radii, each of theplurality of radii extending from one of the plurality of centerpoints.7. The nozzle of claim 6, wherein the curvilinear profile is furtherdefined by a minimum distance between the one of the inner sidewallpressure side slash face, the inner sidewall suction side slash face,the outer sidewall pressure side slash face, or the outer sidewallsuction side slash face and the leading edge and trailing edge of theairfoil.
 8. The nozzle of claim 1, wherein the airfoil is a plurality ofairfoils.
 9. A nozzle assembly for a turbine system, the nozzle assemblycomprising: a plurality of nozzles disposed in an annular array anddefining a hot gas path, each of the plurality of nozzles comprising: anairfoil comprising exterior surface defining a pressure side and asuction side extending between a leading edge and a trailing edge, theairfoil further defining a tip and a root; an inner sidewall connectedto the airfoil at the tip, the inner sidewall comprising a peripheraledge defining a pressure side slash face, a suction side slash face, aleading edge face, and a trailing edge face; and an outer sidewallconnected to the airfoil at the root, the outer sidewall comprising aperipheral edge defining a pressure side slash face, a suction sideslash face, a leading edge face, and a trailing edge face, wherein atleast one of the inner sidewall pressure side slash face, the innersidewall suction side slash face, the outer sidewall pressure side slashface, or the outer sidewall suction side slash face has a generallycurvilinear profile.
 10. The nozzle assembly of claim 9, wherein thecurvilinear profile is defined by a single centerpoint and a singleradius extending from the centerpoint.
 11. The nozzle assembly of claim9, wherein the curvilinear profile is defined by a plurality ofcenterpoints and a plurality of radii, each of the plurality of radiiextending from one of the plurality of centerpoints.
 12. The nozzleassembly of claim 11, wherein the curvilinear profile is further definedby a minimum distance between the one of the inner sidewall pressureside slash face, the inner sidewall suction side slash face, the outersidewall pressure side slash face, or the outer sidewall suction sideslash face and the leading edge and trailing edge of the airfoil. 13.The nozzle assembly of claim 9, wherein the airfoil is a plurality ofairfoils.
 14. The nozzle assembly of claim 9, wherein the nozzle is afirst stage nozzle.
 15. A gas turbine system, comprising: a compressorsection; a combustor section; and a turbine section, the turbine sectioncomprising a plurality of turbine stages, each of the plurality ofturbine stages comprising a nozzle assembly, the nozzle assemblycomprising a plurality of nozzles disposed in an annular array anddefining a hot gas path, each of the plurality of nozzles comprising: anairfoil comprising exterior surface defining a pressure side and asuction side extending between a leading edge and a trailing edge, theairfoil further defining a tip and a root; an inner sidewall connectedto the airfoil at the tip, the inner sidewall comprising a peripheraledge defining a pressure side slash face, a suction side slash face, aleading edge face, and a trailing edge face; and an outer sidewallconnected to the airfoil at the root, the outer sidewall comprising aperipheral edge defining a pressure side slash face, a suction sideslash face, a leading edge face, and a trailing edge face, wherein atleast one of the inner sidewall pressure side slash face, the innersidewall suction side slash face, the outer sidewall pressure side slashface, or the outer sidewall suction side slash face has a generallycurvilinear profile.
 16. The gas turbine system of claim 15, wherein thecurvilinear profile is defined by a single centerpoint and a singleradius extending from the centerpoint.
 17. The gas turbine system ofclaim 15, wherein the curvilinear profile is defined by a plurality ofcenterpoints and a plurality of radii, each of the plurality of radiiextending from one of the plurality of centerpoints.
 18. The gas turbinesystem of claim 17, wherein the curvilinear profile is further definedby a minimum distance between the one of the inner sidewall pressureside slash face, the inner sidewall suction side slash face, the outersidewall pressure side slash face, or the outer sidewall suction sideslash face and the leading edge and trailing edge of the airfoil. 19.The gas turbine system of claim 15, wherein the airfoil is a pluralityof airfoils.
 20. The gas turbine system of claim 15, wherein the nozzleassembly is a first stage nozzle assembly.